Judy Garland's two songs "I Wish I Were in Love Again" and "Johnny One Note" are sung at the same party, but they were filmed four months apart from each other. You can tell based on the longer length of her hair in the second number and the thicker, belt-less waistline (from a slight weight gain) in the dress she is wearing.
Judy Garland was scheduled only to sing with Mickey Rooney in this film, and producer Arthur Freed offered her $50,000 (or half of what she owed the studio for medical bills) to do one take. At the first public screening, the fans asked for more of her, so Freed offered her another $50,000 to do a second song. By the time her scenes were filmed, she had paid back the studio but had made nothing.
In supplementary material included on the DVD it is noted that Lena Horne's performances in most of the movies of the day, as in this one, are included in a way that permitted them to be cut from the films without damaging the story. This was so that the films could be shown in the American South.
In the movie Lorenz Hart (Mickey Rooney) is upset over being short. In real life he battled homosexuality which was very much looked down on at the time. Since they could not show this in the film they substituted his shortness as the source of his misery.
Cut from the film was Perry Como's rendition of "Lover," leaving only the choral backup and the MGM studio orchestra to play over the opening credits. However, the movie's trailer includes a snippet of Como singing several lines of the waltz. Bonuses on the 2007 DVD release include the trailer and footage of Como's two deleted songs, "Lover" (in a reconstruction of the film's opening sequence, minus the credits) and four takes of "You're Nearer." Audio-only numbers on the DVD include Betty Garrett's complete rendition of "Way Out West," which was truncated in the release print; "My Funny Valentine," also sung by Garrett; "My Heart Stood Still," sung by Como; "I Feel at Home With You" and an extended version of "Manhattan," sung by Mickey Rooney, Marshall Thompson and Tom Drake (dubbed by Bill Lee); "Falling in Love With Love," sung by Gene Kelly; "You Took Advantage of Me" sung by Kelly and Vera-Ellen (in what appears be the only evidence of her own singing voice being used in a Hollywood film), and an extended version of the sequence comprised of "On Your Toes/The Girl Friend/This Can't Be Love," sung by Dee Turner and Cyd Charisse (dubbed by Eileen Wilson) and chorus.
Four Richard Rodgers and Lorenz Hart songs from the 1937 Broadway production of "Babes in Arms" which were showcased in this film hadn't been used in the 1939 Rooney-Garland-Busby Berkeley backyard musical. The numbers are: "I Wish I Were in Love Again," a duet by old pals Mickey Rooney and Judy Garland in the party sequence; "Johnny One Note," Miss Garland's spirited follow-up at the party; Lena Horne's exuberant "The Lady Is a Tramp," which became a signature song for her; and finally, "Way Out West (On West End Avenue)," a comic ditty sung partially by 'Betty Garrett (I)', whose full prerecording can be found on the soundtrack CD from Sony.
The vocals by Perry Como and Mel Tormé were not permitted to be included on the MGM soundtrack album. Como's record label, RCA Victor, issued a single with his commercial recordings of "The Blue Room" and "With a Song in My Heart." Torme, under contract to Capitol Records, waxed a studio rendition of "Blue Moon."
In the marketplace, Judy Garland had two discs of the comically cynical "I Wish I Were in Love Again" - the first recorded at her final Decca session on November 15, 1947, a solo accompanied by the husband-and-wife piano duo, Eadie and Rack; Judy's second on MGM Records, her soundtrack duet with Mickey Rooney, prerecorded on May 28, 1948. Judy's Decca side can be compared to an alternate take on her CD box set from MCA, "The Complete Decca Masters (Plus)." The Rooney-Garland match-up shines on two CD releases: the soundtrack from Sony, along with a Rhino collection, "Romantic Duets From M-G-M Classics."
Lena Horne's prerecording of "Where or When," a standard first heard in the 1937 Broadway show, "Babes in Arms," contains the verse, which was not used in the release print. Her complete rendition was first presented on the MGM Records soundtrack album. In the CD era, there are two offerings of Lena's full version: the soundtrack from Sony and a collection from Rhino, "Lena Horne at Metro-Goldwyn-Mayer: Ain' It the Truth."
Dorothy Rodgers in the film tells Lorenz Hart about 'doing a play with Gene Kelly,' implying that Kelly was already an established stage star by the early 40s. In reality, Kelly was relatively unknown when he was cast in Rodgers and Hart's show 'Pal Joey,' which would also be his only leading role in a Broadway show before going into films.